ABO Contact Lens Fitting 3

Question 1

What is the primary purpose of the edge lift in an RGP contact lens design?

Accepted Answer

Allow tear exchange and lens movement

Answer

Adequate edge lift creates a reservoir beneath the lens periphery, facilitating tear exchange and preventing lens adherence.

Question 2

A scleral lens is most indicated for which of the following conditions?

Accepted Answer

Severe dry eye with irregular corneal surface

Answer

Scleral lenses vault completely over the cornea and land on the sclera, providing a fluid reservoir that benefits both irregular corneas and severe dry eye.

Question 3

Which finding during a slit-lamp evaluation of a soft contact lens wearer suggests giant papillary conjunctivitis (GPC)?

Accepted Answer

Papillae greater than 0.3 mm on the upper tarsal conjunctiva

Answer

GPC is characterized by papillae ≥0.3 mm (often ≥1 mm in advanced cases) on the superior tarsal conjunctiva.

Question 4

When assessing soft contact lens fit, acceptable lens movement after a blink should be approximately:

Accepted Answer

0.2–0.4 mm

Answer

Optimal soft lens movement is 0.2–0.4 mm on primary gaze blink, indicating neither a too-tight nor too-loose fit.

Question 5

A patient wearing silicone hydrogel lenses develops superior epithelial arcuate lesions (SEALs). The most appropriate initial management is:

Accepted Answer

Refit with a flatter base curve or thinner lens

Answer

SEALs are caused by mechanical trauma from a stiff lens edge; refitting with a flatter base curve or thinner lens reduces this mechanical effect.

ABO - American Board of Optometry Practice Test

ABO - American Board of Optometry Practice Test

ABO Contact Lens Fitting 3